Masonry drill



July 31, 1962 L. N. BROWN 3,047,082

MASONRY DRILL Filed March 9, 1960 4 -4 22 51834 iii/g 21 I6 IN VENTOR= La wEL L N. BROWM rates 3,047,632 MASONRY DRILL Lowell N. Brown, 9422Trenton Ave, Overland, Mo. Filed Mar. 9, 1960, Ser. No. 13,897 1 Claim.(Cl. 175-415) The present invention relates generally to drills, andmore particularly to drills that are driven by pneumatic powered means,and are employed to drill openings through, or holes into, concrete orsimilar materials in the masonry category.

Specifically, the present invention is directed to a novel and improvedbit end construction for integral incorporation in this type of drill.

Heretofore insofar as I am aware, the only tools available forattempting to produce circular openings that will extend through amasonry wall or the like are known in the trade as star drills.Similarly, the only tools available for attempting to produce circularsockets, or holes that do not extend all the way through a masonry wallor the like, are likewise known as star drills.

These star drills may have minor differences in the design of their hitends, but all of them have one thing in common. That is to say, each bitend has a salient central point or tip that constitutes the first impactsegment thereof, the wings or other cutting segments of said bit endbeing formed rearwardly of said tip. Consequently in operation, theinitial series of hammer blows concentrate their effectiveness on thesaid central tip portion and cause it to be driven into the surface ofthe masonry in so to speak nail fashion. As a result, radial splits andcrumbling develop about the drill point, so that when the cutting edgesof the bit eventually advance to effective position, the surfacethereabout will have been damaged considerably. Furthermore, inasmuch asthese star drills are advanced bodily, the dislodged material usuallytends to clog, and thusly impair the planar advance of the drills.Consequently as should be apparent, the resulting openings and holestediously produced by means of conventional star drills are seldomcylindrical, and are usually oversized and jagged internally.

Accordingly, the primary object of this invention is to provide a novelbit end concept adapted to overcome the disadvantages of present daystar drills that have been set forth above. 7

It is also an object to provide a bit end of novel configuration adaptedto be integrally formed on one end of conventional drill shanks wherebythe production of circular openings and holes in masonry will beexpedited considerably, and wherein the resultant internal diameters ofsaid openings and holes will at least approximately correspond to thediameters selected.

It is another object of this invention to provide a bit end for amasonry drill having a pair of diametrically opposite tip formations soformed as to automatically effect rotary movements of the drill aboutits axis responsive to power blows directed axially against its bitopposed end.

It is a further object of the invention to provide a bit end portion formasonry drills that is so contoured as to expedite the escape ofgranular and pulverized material from the area being subjected to thedrilling action.

The improved and ingeniously contoured bit end portion for drills of thecategory under consideration is illustrated on a sheet of drawings thataccompanies this specification. It is believed that a more comprehensiveunderstanding of the features of the invention may be had from thedetailed description that follows relatively,

thereto with reference to said drawings wherein:

FIGURE 1 is a plan View of an exemplary masonry drill incorporating abit end portion contoured in accordance with the concepts of the presentinvention;

FIGURE 2 is a side elevational view of the drill illustrated in FIGURE1; I

FIGURE 3 is a bit end elevational view of the drill, on an enlargedscale;

FIGURE 4 is a longitudinal sectional view on an enlarged scale, taken onthe line 4-4 of FIGURE 2;

FIGURE 5 is a longitudinal sectional taken on-the line 55 of FIGURE 3;

FIGURE 6 is an exploded side elevational view of a typical pneumatichammer, and a complemental holder spring wherewith the exemplary drillof FIGURE 1 could be operatively, connected to said hammer;

FIGURE 7 is a side elevational view illustrating a horizontal drillingoperation through a vertical concrete Wall, with the drill operativelyconnected to the hammer by means of said holder spring;

FIGURE 8 is a view showing the horizontal circular hole resulting in thewall, after the drilling operation illustrated in FIGURE 7 had beencompleted; and

FIGURE 9 is a vertical sectional view illustrating a socket produced inan exemplary concrete floor by meansof the present invention, thethreaded shank portion of a bolt being shown above the said socket inposition to be driven thereinto.

With attention directed for the present particularly to FIGURES 1through 5, a masonry drill incorporating the concepts of the presentinvention is designated as a whole by the numeral 10. The drill 10includes a shank portion generally designated 12 that terminates at oneend in a bit portion generally designated 14.

The shank portion 12 is conventional, and includes a cylindrical shank16 that merges into the bit portion 14 at one end, into an integralcollar portion 1 8 at its opposite end, and terminates in an extension20 of reduced diameter, said extension also merging at one end into thecollar portion 18 as shown.

It is again noted at this point, that the present invention is concernedprimarily with the forward or bit end portion 14 of the drillillustrated. Thus the shank portion 12 may be of any desired length, andmay be provided with other appropriate means than the collar portion 18and extension 20 for connecting it toa power operated driving tool.

Said bit end 14 has the novel contour illustrated, and is integrallyformed with the shank 16 of the drill. It comprises a cutter headincluding: a main body 21, a pair of diametrically opposite salientcutting tip formations 22; a diametric cutting edge 24 that is disposedrearwardly of the tip formations 22; two pairs of arcuate cutting edges26 that merge at one end into the tip formations 22 and at the other endinto the cutting edge 24; opposed flat sides 28; and a pair of obliquerearwardly sloping faces 30 that define the diametric cutting edge 24 attheir juncture and merge into the sides 28 at their rear or trailingends 32. As seen to best advantagein FIGURE 3, the salient cutting tipformations 22 are arcuately formed concentric with the shank 16, and thecutting edge 24 extends diametrically between said tip formations fromits mergence at one end into the first pair of arcuate cutting edges 26,to its mergence at the opposite end into the second pair of arcuatecutting edges 26. And as seen to best advantage in FIGURES 2 and 4, theopposed fiat sides 28 of the main body 21 merge into the cylindricalshank 16, and flare therefrom toward the drilling end of the bit tomerge also into the trailing ends 32 of the oblique faces 30.

The outer peripheral surface of each of the tip formations 22 isdesignated 34, and is formed on a radius considerably greater than theradius of the shank 16, so that as should be apparent, these tipformations in operation willproduce and define a hole wherein said shankwould be axially and concentrically disposed but out of contact with thewall of said hole as will appear.

The pair of tip formations 22 each rnerge into the flat sides 28, saidmergence junctures being defined by arcuate edge segments 36 and '38.For reasons to be explained, these arcuate edge segments of each tipformation vary slightly. That is to say, as best seen in FIGURE 1, andwith reference also to FIGURES 3 and 4, the diametrically oppositearcuate edge segments 36 are formed on corresponding radii that aregreater than the radii whereon the diametrically opposite arcuate edgesegments 38 are formed. 7

As best seen in FIGURE 3, the arcuate cutting edges 26, the salient tipformations 22, and the arcuate edge segments 36 and 38 thereof, define apair of opposed generally triangular faces 40 that are connected by thediametric cutting edge 24. Each face 40 is curved from the point of itsmergence into one of the tip formations 22 to its mergence into theadjacent end of the diametric cutting edge 24, and the sides of eachface (constituting the arcuate cutting edges 26), converge to a point atthe end of said diametric edge. e

The opposed sides 28 of the cutter head main body 21, are flat asstated, and flare forwardly from the shank 16. As best seen in FIGURES 2and 5, the peripheral surviewed from the standpoint of the operator.

face of the main body 21 of the bit also flares forwardly from saidshank and merges into the arcuate surfaces 34 of the tip formations 22.a

As hereinbefore indicated the drill shank with its bit end thus fardescribed comprisesthe present invention. The kind of pneumatic hammeror other power device for rapidly reciprocating the drill wouldobviously depend on the resultant circular opening or hole contemplated.

An exemplary power means is illustrated in FIGURES 6 and 7, andcomprises a pneumatically operable hammer H of the gun type. Itincludes: a handle a depending from a cylindrical section b; a flexibleline c for supplying power to the hammer from a source of compressedair; an appropriate manually operable air pressure control devicedesignated d; and a barrel e projecting from the cylindrical section b.

An appropriate mechanism for automatically reciproeating a pistonresponsive to manipulations of the control device d is located partiallyin the barrel e and partially in the cylindrical section b. However, itis not deemed necessary to illustrate and describe this pistonreciprocating mechanism, nor the air passageways associated therewith.Reference may be had if desired, to United States Letters Patent No.2,655,901 issued to me on October 20,

1953, for a comprehensive disclosure of means for eflecting reciprocalpiston movements in a pneumatic hammer.

Formed externally in the free end portion 1 of the barrel e I is aplurality of annular grooves each designated g. These grooves serve,with the aid of a suitable holder spring, to operatively connect toolshanks such as that illustrated, .to the barrel: in proper position toreceive intermittent power blows directed thereagainst by thereciprocating piston of the hammer, as is understood. A suitable holderspring h of the beehive type is illustrated per seat the left in FIGURE6. By means of the spring h, or one of similar nature, the drill 12 maybe. operatively connected to the hammer as is well understood, and isdemonstrated in FIGURE 7. As a general rule, it'has been foundadvantageous to incorporate in pneumatic hammers of this type, means fordirecting the air exhaust forwardly past the barreland away from thehand of the operator.

Although it is believed apparent that the novel configuration of the bitend '14 disclosed herein is adapted to achieve the primary objectives ofthe invention in 'a highly efficient manner, a brief explanation will begiven, with particular attention being directed first to FIGURES 7 and8.

Shown in FIGURE 7 is a fragmentary portion of a vert cal wall W that isindicated tobe of concrete, although to accommodate the slidable passagetherethrough of a conduit having an external diameter of oneand one halfinches. In accordance with the concepts of the present invention,a'drill 12 provided with a bit end portion 14 that has its salient tipformations 22 formed on a three quarter inch radius would be selected,and operatively connected to the pneumatic hammer H by means of theholder spring 11. Thereupon, with the hammer in readiness for operationvia manipulation of the control device d as is understood, the drill 12would be directed against the wall W in the selected horizontal plane. IThe first hammer blow would cause the salient tip formations 22 topenetrate the wall surface followed by further penetration as the hammerblows continue in rapid succession. Concurrently with its advance, thedrill would automatically be caused to rotate about its axis inconsequence of the described arcuate dissimilarity of the edges 36 and38.

In other words, following the initial and the immedi-v ately succeedinghammer blow, the drill 10 would automatically begin to rotate in aclockwise direction as At first, the rotation would be slight, perhapsfive or ten degrees, dependent on the density of the material into whichthe drill is being driven. The rapidity wherewith the hammer blows aredelivered make it diflicult to define the precise degree of drillrotation. In the case of an ordinary concrete wall for example, therotary movements of the drill, once initiated and continued for a shorttime, would approximate forty-five degrees. In the case of a stone wallhowever, such rotary movements could be of a lesser degree. At any rate,the degree of drill rotation would be incremental until a completecircular cavity had been produced.

When the drill is driven into a partially formed open- 5 is in advanceof the mergence of the cutting edges 36 Furthermore with respect to thecentera into said sides. line, the expanse of cutting surfacesth-atobtain along the salient tip formations 22 between the mergencesthereinto 0f the cutting edges 38 is greater than the similar 8111'?faces that obtain along said formations between the thergences thereintoof the arcuate cutting edges 36.

Consequently, as the salient cutting tip formations 22 repeatedlyimpinge against the material, the reaction forces against the largerdiametered arcuate edges 38 overcome the reaction forces against thesmaller diametered arcuate edges 36, thus automatically effecting arotational movement of the drill toward the latter edges.

Immediately following the initial succession of hammer blows, thediametn'c cutting edge 24 will disintegrate the annular body of concreteabout which the tip formations 22 are cutting a circular groove.Concurrently, the pairs of arcuate cutting edges 26 that constitute thesides the material as they come into contact therewith; All

of the disintegrated and simultaneously pulverized mate rial is directedangularly outwardly from the axis of V the bit via the rearwardlysloping faces 30. As the granular and pulverized material is deflectedrearwardly by the sloping faces 30, it flows past the sides 28 and intothe annular space about theshank 16 in that portion of the circularopening already drilled and leading rearwardly to atmosphere. This is animportant feature of the invention. In other words, these flat sidestogether path the flared surfaces 21 provideample space rearwardlyof theactual cutting edges for facilitating the escape of the; .material. Theescape of the granular and pulverized material is further facilitated bythe turbulence created in the opening in consequence of the exhaust airblasts directed thereinto from the hammer, as should be apparent.

FIGURE 7 demonstrates a stage wherein the drilling operation withrespect to the circular opening in contemplation has been partiallycompleted. The path of the expelled pulverized material is suggested bythe arrows. The final drilled opening is shown in FIGURE 8. As thereillustrated, the internal peripheral surfiaces of the opening aresmooth, and the diameter of said opening is of the desired size.

With attention directed to FIGURE 9, it will be assumed that theconcrete floor F there fragmentarily illustrated represents a floor in amanufacturing plant or the like. It will also be assumed that it isdesired to bolt the legs of a lathe or other piece of machinery to saidfloor. It will further be assumed that the threaded shanks s of thebolts to be employed for the purpose have diameters of one andone-eighth inches.

In order to drill suitable holes for engagement by said shanks, a drill10 provided with a bit end portion 14 that has its salient tipformations 22 formed on a onehalf inch radius would be selected, andoperatively connected to the pneumatic hammer H by means of a holderspring h.

Thereupon with the drill 10 directed vertically downwardly, the circularsocket or hole illustrated in said FIG- URE 9 would be drilled to anappropriate depth.

From the foregoing description augmented by an inspection of thedrawings, it should be apparent that the present invention provides anovel masonry drill bit end that achieves its objectives in a highlyeflicient manner. It should further be evident that angularly disposedcircular openings and holes may be drilled, and that the shankconstruction may be varied and per se comprises no part of the presentinvention.

What I claim is:

A bit end for a power operated drill wherewith to drill a circularopening through or into masonry, said bit end being integrally formedtherewith on the head end of the cylindrical shank of said drill andcomprising in combination: a main body having opposed flat sides eachmerging into said shank and flaring forwardly from its mergencethereinto, said body terminating in a pair of diametrically oppositesalient cutting tip formations concentric with said shank, theperipheral surfaces of the tip formations being formed on -a radiusconsiderably greater than that whereon the shank is formed; two pairs ofcircumferentially spaced diametrically opposite arcuate edge segmentsforming the extremities of said salient tip formations and merging intothe flat sides of said main body, one of each pair of circumferentiallyspaced edge segments being formed on a radius larger than that whereonthe other is formed, with the diametrically opposite edge segments beingformed on corresponding radii; a diametric cutting edge disposedrearwardly of the salient tip formations and extending longitudinallybetween them; two pairs of arcu-ate' cutting edges, each of said arcuatecutting edges merging at its outer end into one of the salient tipformations and at its inner end into one extremity of the di'ametriccutting edge, each pair of arcuate cutting edges converging to a pointat the mergenoe of them into said diametric cutting edge; a pair ofopposed generally triangular faces that are connected by the diametriccutting edge and merge into the salient tip formations, each of saidfaces being curved rearwardly from the point of its mergence into one ofsaid tip formations to its mergence into the adjacent end of saiddiametric cutting edge, the sides of said faces being defined by thearcuate cutting edges aforesaid; and a pair of oblique rearwardlysloping faces that converge to define the diametric cutting edge attheir forward juncture and merge at their rearward ends into the flatsides aforesaid of the main body.

References Cited in the file of this patent UNITED STATES PATENTS202,023 Grubs Apr. 2, 1878 1,098,795 Gill June 2, 1914 1,483,296 GillFeb. 12, 1924

